1. Field of the Invention
The present invention, in a fan coupling apparatus for supplying to an engine an amount of cooled air that is always automatically adjusted according to the running state of a vehicle, and for controlling according to changes in revolution or in the temperature of the surrounding external environment the rotation of a fan for cooling an engine in a common automobile or other vehicle, relates to a hydraulic fan coupling apparatus comprising especially a fan member entity that is directly united with a hermetically sealed case.
2. Description of the Related Art
In general, conventional fan coupling apparatuses of this type, as shown in FIG. 4 and FIG. 5, are comprised of a fan member F--either formed from metallic fan blades 20' that are riveted to a star-shaped, steel-plate spider 20 (FIG. 4), or from plastic fan blades 21' that are molded onto the external portions of a round plate-shaped, steel-plate insert 21--that is separately attached by bolts via the spider portion or the insert portion into a hermetically sealed case that is the driven side of the fan coupling apparatus.
However, with these types of prior art fan coupling apparatuses, there are many problems, including the fact that the above-described separately formed fan member F requires press molding of the spider 20 or of the insert 21; moreover, the work of attaching this fan member to the hermetically sealed case increases the amount of labor required. At the same time, the increased load on the bearing portion--due to the cantilevered bearing support--that accompanies the increased weight on the driven side is a cause of early abrasion, and can easily result in unwanted shaking (rattling) of the apparatus. In addition, productivity is undesirably lowered due to the fact that a dynamic balance adjustment must be performed not only for the fan member unit itself, but, following the attachment of the fan member to the hermetically sealed case, another dynamic balance adjustment must be performed for the finished product.